1. Field of the Invention
The present invention relates to so-called fit plug type optical connectors in which optical coupling is performed through guide pins.
2. Description of the Related Art
Heretofore, MF optical connectors and MT optical connectors are known as conventional optical connectors having guide holes. Such optical connectors provide optical coupling in a manner that guide pins are inserted into guide holes of respective optical connectors and optical fibers are made to abut on each other at their end surfaces while positioning the optical connectors.
In such a conventional optical connector, however, the inner diameter of a guide hole is generally formed so as to be slightly larger (about 1 to 3 .mu.m) than the diameter of a guide pin in order to facilitate an attaching/detaching operation. As a result, the optical connector may move by a clearance defined between the inner diameter of the guide hole and the outer diameter of the guide pin when the optical connector is coupled with another optical connector. This presents a problem in that coupling loss varies at the time of attachment/detachment of the optical connectors.
For example, if there is a displacement by 1 .mu.m in a direction perpendicular to the axial line of the optical fibers when optical connectors having a coupling loss of 0.2 dB are coupled with each other, the coupling loss increases to about 0.8 dB.
Further, when a ferrule is produced by molding with a plastic material, the guide holes cannot be always straight and may be curved because of the unevenness of shrinkage, the warp, or the like, of the molding material. In such a case, the position in which the guide pin is in contact with the guide pin varies correspondingly to the individual ferrule. This presents a problem in that the fitting state of the guide pin is varied rather than fixed.
Furthermore, the position at which the guide pin is located with respect to the guide hole in the longitudinal direction is not fixed, thereby allowing the coupling state of the connectors to vary correspondingly to the location of the guide pin.